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Abstract:
The purpose of this study was to evaluate the effects of wearing MCU- 2/P and M-17 groundcrew chemical defense masks during steady-state work. Five MCU-2/P mask configurations (MC) were tested: mask without filter (MCU-OF), mask + 1 filter (MCU-1F), mask + 2 filters (MCU-2F), mask + 1 filter + air blower A (MCU-ABA), and mask + 1 filter + air blower B (MCU-ABB). Ten subjects walked on a treadmill (3 mph - 5.0% grade) for 1 hr wearing each MC. Variables measured included inspiratory and expiratory mask cavity pressures (IMCP and EMCP), mask cavity pressure-swing (MCPS), peak inspiratory airflow rate (PIAFR), respiratory rate (RR), peak tidal volume (PTV), minute volume (MV), heart rate (HR), rating of perceived exertion (RPE), perceived inspiratory and expiratory effort (PIE and PEE), and overall breathing discomfort (OBD). Each MC was characterized by a significantly different IMCP. The MCU-ABA produced the lowest IMCP, while MCU-1F produced the highest. MCU-2F reduced inspiratory resistance by about 47%. There were no significant differences in PIAFR, RR, PTV, MV, RPE, PIE, PEE, and OBD among the various MC. The new MCU-2/P mask does not improve total breathing resistance over the standard M-17 mask. Neither mask should induce significant cardiorespiratory strain providing the physical work is of low intensity. A very effective (but logistically difficult) approach to reduce the level of inspiratory resistance imposed by the MCU-2/P mask is to provide powered ventilation as compared to the relatively simple installation of a second filter.... Breathing resistance, Protective mask, Exercise, Ventilation, Perceived effort.
| Limitations: |
 APPROVED FOR PUBLIC RELEASE |
| Description: |
Final rept. May 91-Jan 92 |
| Pages: |
39 |
| Report Date: |
MAR 93 |
| Contract Number: |
F33615-89-C-0603 |
| Report Number: |
A122562 |
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